Accurate Atomic and Molecular Wave Functions Without Exchange
Abstract
A perturbationtheoretic procedure is developed for obtaining the spatial function Φ_{0} for the manyelectron problem, from which the total wave function can be projected by the relation Ψ=iD~_{i0}(r)D_{i0}(σ)Φ_{0}(r)χ_{0}(σ). This function is expanded in a perturbation series in which the Φ_{0}^{0} contains a sufficient set of pair symmetries of Φ_{0} itself, such as in the Hartree nonantisymmetrized wave function for closedshell atoms. When the expansion converges, the remaining symmetries are introduced exactly. The energy eigenvalue does not contain the usual "exchange" terms, since the zerothorder Hamiltonian, unlike the HartreeFock H_{0}, has no degeneracies. Applications to interaction energies in molecular crystals and asymmetric wave functions are discussed briefly.
 Publication:

Physical Review
 Pub Date:
 October 1968
 DOI:
 10.1103/PhysRev.174.94
 Bibcode:
 1968PhRv..174...94M